The present invention relates to a food extruding apparatus for extruding soft foods or food materials to form food products having a fibrous texture.
More practically, the present invention pertains to a food extruding apparatus for use in the production of foods having a fibrous texture which is similar to that of the eyes of scallops or the leg meat of crabs.
The following is one example of the conventionally known processes for manufacturing products having a fibrous texture such as that described above. Namely, raw minced fish meat is kneaded under stirring, molded or shaped, allowed to gel and heated to form a fish cake which is usually employed as a final product. Thereafter, this fish cake is finely cut in the shape of fibers, and this finely cut fish cake is texturized using a binding agent or the like and then molded into a desired shape again, thereby providing a fish paste product having a fibrous texture. Alternatively, the finely cut fish cake is mixed with minced fish meat, integrally molded and heated to prepare a fish paste product having a fibrous texture.
The applicant of the present invention filed an application for a patent titled "Fibrous Fish Paste Product and Process for Producing the Same" on May 26, 1977 [Japanese patent application No. 60441/1977 (Japanese patent Laid-Open No. 145954/1978)]and disclosed therein a novel fish paste product having a fibrous texture and a process for producing the same.
The feature of the invention of the previous application resides in that minced fish meat is finely cut in the shape of fibers before it is heated, that is, after it has been molded and allowed to gel, and the finely cut material is then heated to obtain a final product. To finely cut the material in the shape of fibers, the minced fish meat is extruded through a net made from, for example, a wire having a diameter of about 1 mm. The minced fish meat is in a gel state at this stage. Therefore, the minced fish meat which has been passed through the net so as to be finely cut does not break up but maintains its previous integral configuration. If this minced fish meat is heated a final product having the initial integral configuration is obtained. This final product minced fish meat comes apart into small pieces when eaten as it has been finely cut by the net when passing through the same, and this gives the sensation of eating the eye of a scallop or the leg meat of a crab.
In contrast to the aforementioned conventional method, the method according to the invention of the previous application does not involve the need to carry out the step of finely cutting the fish cake once produced by heating the minced fish meat in a gel state and recollecting the small pieces of the cut meat so as to mold them into a desired shape, and therefore enables a fish paste product having a fibrous texture to be prepared in a reduced number of steps.
Since the invention of the previous application was first accomplished, various types of food producing apparatus for putting it into practical use have been developed. However, there has heretofore been no apparatus capable of efficiently and properly extruding minced fish meat into a product having a fibrous texture.
A previously developed apparatus had an arrangement in which an amount of minced fish meat suitable for one fish paste product, which has been allowed to gel, is charged into a cylinder-like member, and a piston-like member is forced into the cylinder-like member from one open end thereof in such a manner that the minced fish meat is extruded through a net member stretched over the other open end of the cylinder-like member. This apparatus, however, involves the following problem. Since the minced fish meat possesses sticky consistency, when it is extruded by the piston-like member, the rearmost end portion of the material is attached to the net and does not separate from it. If, in this state, the piston-like member is returned, a vacuum is produced between the attached fish meat material and the piston-like member, thus causing the material to be drawn back into the cylinder-like member.
In order to solve this problem, an arrangement has been proposed in which a through-hole is provided in the piston-like member, so that, when the piston-like member is pulled back, the air is allowed to enter the area between the piston-like member and the attached minced fish meat. It has, however, been found that this through-hole may become clogged with the minced fish meat, and this arrangement is therefore unable to overcome the above-described problem.
To prevent the through-hole from being clogged with minced fish meat, another arrangement has been devised in which a check valve is provided at one end of the through-hole, and the through-hole is opened only when the piston-like member is pulled back. However, this arrangement has also been found to be unsatisfactory because the structure is undesirably complicated and, in addition, the check valve often suffers certain troubles due to the adhesion of the minced fish meat.
Problems similar to the above may arise also when soft foods (or soft food materials) are extruded to form products (or semi-finished products).